In this study, the medical examinations included obtaining a
detailed occupational history, significant medical history, past and
current noise exposure history as well as compliance with usage of
hearing protective devices, and physical examination, which
included body mass index and otoscopic examination for external
ear conditions such as ear drum perforation, ear wax impaction, or
external ear infections. Other tests such as full blood count, fasting
blood sugar, fasting cholesterol, liver function tests, renal function
tests, and urine microscopy as well as audiometry test, were also
carried out to complete the medical examination. The audiometry
test was conducted at least 16 hours after the last noise exposure to
exclude temporary threshold shift, a condition where there is
temporary hearing loss after noise exposure.